From 0bf77e9dbb5247ae159342db6f8fdb48aba24b56 Mon Sep 17 00:00:00 2001 From: Ming Lin Date: Mon, 25 Apr 2016 14:20:18 -0700 Subject: [PATCH] nvme: switch to RCU freeing the namespace Switch to RCU freeing the namespace structure so that nvme_start_queues, nvme_stop_queues and nvme_kill_queues would be able to get away with only a RCU read side critical section. Suggested-by: Christoph Hellwig Signed-off-by: Ming Lin Reviewed-by: Christoph Hellwig Reviewed-by: Keith Busch Reviewed-by: Sagi Grimerg Signed-off-by: Jens Axboe --- drivers/nvme/host/core.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 3cf366ab66e9..3428c0232403 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1429,7 +1429,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid) if (nvme_revalidate_disk(ns->disk)) goto out_free_disk; - list_add_tail(&ns->list, &ctrl->namespaces); + list_add_tail_rcu(&ns->list, &ctrl->namespaces); kref_get(&ctrl->kref); if (ns->type == NVME_NS_LIGHTNVM) return; @@ -1467,6 +1467,7 @@ static void nvme_ns_remove(struct nvme_ns *ns) mutex_lock(&ns->ctrl->namespaces_mutex); list_del_init(&ns->list); mutex_unlock(&ns->ctrl->namespaces_mutex); + synchronize_rcu(); nvme_put_ns(ns); } @@ -1751,8 +1752,8 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl) { struct nvme_ns *ns; - mutex_lock(&ctrl->namespaces_mutex); - list_for_each_entry(ns, &ctrl->namespaces, list) { + rcu_read_lock(); + list_for_each_entry_rcu(ns, &ctrl->namespaces, list) { if (!kref_get_unless_zero(&ns->kref)) continue; @@ -1769,7 +1770,7 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl) nvme_put_ns(ns); } - mutex_unlock(&ctrl->namespaces_mutex); + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(nvme_kill_queues); @@ -1777,8 +1778,8 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl) { struct nvme_ns *ns; - mutex_lock(&ctrl->namespaces_mutex); - list_for_each_entry(ns, &ctrl->namespaces, list) { + rcu_read_lock(); + list_for_each_entry_rcu(ns, &ctrl->namespaces, list) { spin_lock_irq(ns->queue->queue_lock); queue_flag_set(QUEUE_FLAG_STOPPED, ns->queue); spin_unlock_irq(ns->queue->queue_lock); @@ -1786,7 +1787,7 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl) blk_mq_cancel_requeue_work(ns->queue); blk_mq_stop_hw_queues(ns->queue); } - mutex_unlock(&ctrl->namespaces_mutex); + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(nvme_stop_queues); @@ -1794,13 +1795,13 @@ void nvme_start_queues(struct nvme_ctrl *ctrl) { struct nvme_ns *ns; - mutex_lock(&ctrl->namespaces_mutex); - list_for_each_entry(ns, &ctrl->namespaces, list) { + rcu_read_lock(); + list_for_each_entry_rcu(ns, &ctrl->namespaces, list) { queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, ns->queue); blk_mq_start_stopped_hw_queues(ns->queue, true); blk_mq_kick_requeue_list(ns->queue); } - mutex_unlock(&ctrl->namespaces_mutex); + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(nvme_start_queues);